<?php
echo 1_5_3_432_329,"\n";//十进制整数，可以用下划线分组
echo 032,"\n";//以0开头，后边是0-7，8进制整数
echo 0o32,"\n";//以0o开头，后边是0-7，8进制整数
echo 0b1101,"\n";//以0b开头，后边是0-1，2进制整数
echo 0x49A,"\n";//以0x开头，后边是0-9A-F，16进制整数,所有字母不区分大小写
//算数算运符
echo 8 / 5,"/n";
echo intdiv(8,5),"\n";//只有整数部分
echo 8 % 5,"\n";//两个整数相除取余数
echo @(8.1 % 5.9),"\n";//两个整数相除取余数,@用来抑制警告信息
echo (int)8.1 % (int)5.9,"\n";//两个整数相除取余数,明确强制类型转换
echo fmod(8.6,5),"\n"; //3.6
echo 2**3,"\n";//2的3次方
//和其他类型的数据进行运算
echo 12+3.5,"\n"; //转换为float进行计算
echo 1200+"12abc","\n";//"12abc"不以数字开头，转换为12，结果1212
echo 1200+"3e4yy","\n";//"3e4yy",3乘以10的4次方，转换为30000，结果31200
//echo 1200+"abc12","\n";//"12abc"不以数字开头，错误
//echo 1200+"","\n";//""不以数字开头,错误
echo 1200+true,"\n";//true转换为整数1，结果1201
echo false+1200,"\n";//false转换为整数0，结果1200
echo null+1200,"\n";//null转换为整数0